title: Action of acetylxylan esterase from Trichoderma reesei on acetylated methyl glycosides.
abstract: Substrate specificity of purified acetylxylan esterase (AcXE) from Trichoderma reesei was investigated on partially and fully acetylated methyl glycopyranosides. Methyl 2,3,4-tri-O-acetyl-beta-D-xylopyranoside was deacetylated at positions 2 and 3, yielding methyl 4-O-acetyl-beta-D-xylopyranoside in almost 90% yield. Methyl 2,3-di-O-acetyl beta-D-xylopyranoside was deacetylated at a rate similar to the fully acetylated derivative. The other two diacetates (2,4- and 3,4-), which have a free hydroxyl group at either position 3 or 2, were deacetylated one order of magnitude more rapidly. Thus the second acetyl group is rapidly released from position 3 or 2 after the first acetyl group is removed from position 2 or 3. The results strongly imply that in degradation of partially acetylated beta-1,4-linked xylans, the enzyme deacetylates monoacetylated xylopyranosyl residues more readily than di-O-acetylated residues. The T. reesei AcXE attacked acetylated methyl beta-D-glucopyranosides and beta-D-mannopyranosides in a manner similar to the xylopyranosides.
authors.affiliation: Institute of Chemistry, Slovak Academy of Sciences, Bratislava. chempbsa@savba.sk
authors.forename: P
authors.initials: P
authors.lastname: Biely
authors.forename: G L
authors.initials: GL
authors.lastname: Côté
authors.forename: L
authors.initials: L
authors.lastname: Kremnický
authors.forename: R V
authors.initials: RV
authors.lastname: Greene
authors.forename: M
authors.initials: M
authors.lastname: Tenkanen
mesh_terms: D000107:Acetylation; D000115:Acetylesterase / Q000378:metabolism*; D002236:Carbohydrate Conformation; D002855:Chromatography, Thin Layer; D005656:Fungal Proteins / Q000378:metabolism; D005960:Glucosides / Q000378:metabolism; D006027:Glycosides / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D008362:Mannosides / Q000378:metabolism; D013379:Substrate Specificity; D014242:Trichoderma / Q000201:enzymology*; D014990:Xylans / Q000378:metabolism
chemical_list: D005656:Fungal Proteins; D005960:Glucosides; D006027:Glycosides; D008362:Mannosides; D014990:Xylans; C010807:xylosides; D000115:Acetylesterase; C081851:acetylxylan esterase